The present invention relates to 2-isopropenyl-5-methyl-4-hexen-1-yl 3-methyl-2-butenoate (generic name: lavandulyl senecioate) as a sex pheromone component of vine mealybug (scientific name: Planococcus ficus).
Vine mealybug (scientific name: Planococcus ficus) is known as one of major insects of grapevines and damages fruits of grapevines, causing serious problems such as reductions in the yield and the crop quality. At the present time, insecticides are used to control the vine mealybug without sufficient success. Because of concerns about the environment and human health affected by the use of insecticides, there is a demand for the development of novel insect pest control methods such as mating disruption and mass trapping by using sex pheromone substances.
The sex pheromone substance that is secreted by females of the vine mealybug and is used for reproductive behavior is 2-isopropenyl-5-methyl-4-hexen-1-yl 3-methyl-2-butenoate (generic name: lavandulyl senecioate), which has been reported by Diane M. Hinkens et al. (Tetrahedron Letters 42 (2001) 1619-1621).
The existing method for producing 2-isopropenyl-5-methyl-4-hexen-1-yl 3-methyl-2-butenoate is exemplified by the method reported by Diane M. Hinkens et al. (Tetrahedron Letters 42 (2001) 1619-1621). In the method, senecioyl halide prepared by halogenation of senecioic acid is reacted with 2-isopropenyl-5-methyl-4-hexen-1-ol in the presence of an organic base. However, when the compound is produced in an industrial scale by the method of Hinkens et al., by-products are formed during the purification by distillation to lower the yield. To address the problem, WO 2008/075468 discloses the method in which an unpurified 2-isopropenyl-5-methyl-4-hexen-1-yl 3-methyl-2-butenoate is heat-treated in the presence of a basic substance and then is purified by distillation.
Another production method is also reported in WO 2006/109570. In the method, a sulfonate ester prepared from 2-isopropenyl-5-methyl-4-hexen-1-ol and an organic sulfonyl halide is reacted with senecioic acid in the presence of a basic substance.